New evidence for enhanced ocean primary production triggered by tropical cyclone

TLDR

In July 2000, moderate cyclone Kai‑Tak passed over the South China Sea. The study uses recent satellite data to quantify the contribution of tropical cyclones to ocean primary production. Kai‑Tak caused a 30‑fold rise in surface chlorophyll‑a, fixing 0.8 Mt of carbon—about 2–4 % of the South China Sea’s annual production—and, extrapolating from 14 annual cyclones, tropical cyclones may contribute 20–30 % of the region’s yearly new production.

Abstract

New evidence based on recent satellite data is presented to provide a rare opportunity in quantifying the long‐speculated contribution of tropical cyclones to enhance ocean primary production. In July 2000, moderate cyclone Kai‐Tak passed over the South China Sea (SCS). During its short 3‐day stay, Kai‐Tak triggered an average 30‐fold increase in surface chlorophyll‐a concentration. The estimated carbon fixation resulting from this event alone is 0.8 Mt, or 2–4% of SCS's annual new production. Given an average of 14 cyclones passing over the SCS annually, we suggest the long‐neglected contribution of tropical cyclones to SCS's annual new production may be as much as 20–30%.